1. Field of the Invention
The present invention relates to an electrostatic copying apparatus in which, after an electrostatic latent image of an original document is formed on a photosensitive member by exposure of the original document by a movable optical device, the image is transferred to a copy sheet and is fixed.
2. Description of the Prior Art
In a conventional electrostatic copying apparatus, the cycle of a copying operation is such that a copy sheet is supplied from a copy sheet feed means such as a feed cassette to a copy sheet transport path. Along this transport path a toner image on a photosensitive member developed by applying toner particles thereto is transferred to the copy sheet, and the copy sheet then is transported to a fixing device and is discharged. This transport path for transporting a copy sheet generally extends for a relatively long distance. In case of paper jamming along the long transport path, generally jamming is indicated visibly. Jamming is detected by means of only a few switches for detecting the copy sheet disposed along the transport path. Therefore, when jamming occurs, a copy sheet is damaged, a subsequent sheet is supplied in a multiple copy operation, or a jammed sheet is burnt in a heat fixing device, and thus further faults are inclined to develop.
It is an object of the invention to provide an improved electrostatic copying apparatus for solving technical problems as above-mentioned.
It is another object of the invention to release an apparatus housing easily so that a jammed sheet may be removed from a copy sheet transport path.
It is a further object to provide an improved display means for indicating jamming immediately.
It is a further object to prevent malfunction or troubles due to jamming from causing other faults within the electrostatic copying apparatus.
Another prior art apparatus comprises a cleaning device including a photosensitive drum whose surface is in contact with a furred brush for scraping residual toner particles remaining on a surface of the drum after completion of the transferring step. Therefore the furred brush injures the photosensitive drum.
A more particular object of the invention is to provide a new and improved transport means for causing magnetic toner particles to advance by their magnetic force so that mechanical members are not in contact with the photosensitive drum.
Generally, after transferring, residual toner particles on a photosensitive surface of the drum are cleaned by a cleaning device, and removed particles are stored in a sump. An operator has to release an apparatus housing every time so as to recognize whether the sump is full of removed toner particles. Such operation takes much time and is troublesome.
It is a still further object of the invention to provide an improved detecting device for detecting automatically the quantity of toner particles in the sump.
It is a further object of the invention to retain an adjustable charged surface of the photosensitive member and to reproduce a clear transferring image during each copying operation.
These and other objects will becomes more apparent from the following brief description and drawings.